1. Field of the Invention
The present invention relates to paper shredders and, in particular, to paper shredder thickness detectors.
2. Background Art
Unintended misuse of a paper shredder most often can be caused by feeding too many sheets of paper into the shredder paper feed mechanism at a time. Such misuse is a significant root cause for paper shredder malfunctions. Although a paper shredder may specify a maximum page count and paper weight for shredding, most users tend to feed the shredder using a “feel and experience” that can lead to overload due to paper thickness (weight) variances, misjudgment in the amount of shreddant inserted into the paper feed inlet, or inexperience with the paper shredder. As a result, feeding a bolus of shreddant that has too many sheets, that is too heavy (e.g., paper weight/thickness), or both leads to paper jam, causing the shredder to stop.
Paper jams exert unnecessary torque onto the shredder electric motor, gear drives, and cutting mechanism, leading to premature wear and failure of such parts. Excessive torque can arise from too many plies of shreddant being forced into the paper shredder feed opening at one time. Also, over time, the cutting mechanism of the shredder tends to wear and to lose capacity for shreddant. In general, as a shredder gets older and with wear, the maximum shredder capacity is reduced.
Current built-in devices that measure or detect shreddant thickness do not compensate for dulling of the shredder blades, accumulated misalignments, and general wear on the shredder mechanism over time. Often small blade misalignment errors may grow over time and may contribute to additional torque, wear and malfunctions. Paper shredders outfitted with auto-reverse functions also can suffer from misuse and misalignment. Meshing of cutting parts may become inefficient in this mode of operation and may further harm the shredding mechanism with excessive torque. A better thickness detector can assist in reducing shredder machine wear and malfunction.